ÖVGW is committed to making a contribution to climate change and is converting the natural gas grid completely to climate-neutral gases by 2040. The currently existing Austrian natural gas grid is a valuable part of the energy infrastructure for distribution, storage and transport of large amounts of energy within the country, as well as across national borders. The aim of the BIG - GreenGas project is to research new processes to upgrade biogenic residues to green gas and thus to raise the regional potential for climate-neutral gases in Austria. For this purpose, DFB gas production with subsequent production of synthetic natural gas (SNG) and hydrogen (H2) were selected as potential technologies. Austrian biogenic residues, which are currently not put to any material use, are to serve as feedstock.

In order to quantify the potential of green gas production in Austria, first the regional availability of biogenic residues was surveyed, which could be suitable for use in gas production. Selected residues are tested for their suitability in the 1 MW gasifier of the Syngas Platform Vienna and the obtained product gas can subsequently be tested for the production of SNG or hydrogen. Based on the experimental data, the costs of the production chains can be estimated, a life cycle assessment can be performed, and recommendations on necessary adaptations of existing ÖVGW guidelines (e.g. limit values for impurities adapted to SNG) can be given. The project runs for a total of 3 years, the results of the first project year are presented below.

Results of the biomass potential analysis (left), achievable product gas composition of an optimised gasification with bark (middle), as well as the upgrading to SNG and H2 considered in the following years (right) and the ecological and economic evaluation (bottom).

Results of the first project year

The technical potential of the considered biomass assortments amounts to about 3.5 million t dry matter or 12 TWh CH4 per year. The wood-based assortments account for almost 55% of the calculated methane yield. Based on the surveyed biomass potentials, bark was selected as the first fuel for demonstration. Gasification with bark could be carried out successfully and the operation was comparable to previously used wood chips. Simulations of optimized operation at 1 MW demonstration scale showed a cold gas efficiency of 68% from fuel to product gas, and this without the use of fossil additive fuels. In the tested fine gas cleaning, it was also possible to remove tar impurities, allowing further use of the product gas for SNG and H2 production.

In parallel with the technical demonstration, a life cycle assessment of the processes will be performed. The literature shows that the processes can be designed in such a way that the impact is significantly lower than that of the fossil reference (natural gas, fossil hydrogen).